Field of the Invention
The present invention relates to an aqueous ophthalmic composition.
Description of the Related Art
Carbonic anhydrase inhibitors used in ophthalmic compositions are generally solid and insoluble or hardly soluble in aqueous solvents such as water that are usually used as ophthalmic carriers. Brinzolamide, which is effective as a carbonic anhydrase inhibitor, is also hardly soluble in water. Therefore, at present, carbonic anhydrase inhibitor-containing ophthalmic compositions are used in the form of a suspension. However, in a case in which a carbonic anhydrase inhibitor-containing ophthalmic composition is used in the form of a suspension, it is concerned that, at the time of the administration thereof to the eye, solid particles in the suspension block light and obstruct the field of vision, temporarily causing a phenomenon of blurred vision.
Further, in the use of such an ophthalmic composition in the form of a suspension, it is also concerned that the administration thereof to the eye may cause irritation to the eye if the solid component has a large particle size. Therefore, it is required that solid particles contained in the suspension be fine.
As a method of preparing a suspension including brinzolamide or the like that is effective as a carbonic anhydrase inhibitor, there has been proposed a method of preparing a suspension in which a solution containing brinzolamide and a surfactant is subjected to wet grinding and a thickening agent such as a carboxyvinyl polymer is incorporated into the resulting suspension (see, for example, International Patent Publication No. WO 2012/053011).
Further, Japanese National-Phase Publication (JP-A) No. 2013-512894 discloses a method of preparing a dispersion including carbonic anhydrase inhibitor particles, which method includes: autoclaving a uniformly dispersed slurry containing a carbonic anhydrase inhibitor and a surfactant; sizing the carbonic anhydrase inhibitor particles in the slurry using a microfluidizer; and subsequently mixing the thus processed slurry with a solution that contains water and a polymer such as hypromellose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, or sodium carboxymethyl cellulose.
Moreover, there is proposed a method of producing a brinzolamide dispersion, in which a dispersion is prepared by adding an aqueous solution of a carboxyvinyl polymer to a dispersion including brinzolamide and a surfactant (see, for example, WO 2013/17528).